A lot of religious people are practical atheists and don't respect all the commandments their god imposes. This happens frequently, at least partially, the prime example being premarital sex, I have a lot of christian friends but really how many of them refrain from that particular sin?
Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you